Its own name and contact address (mail address and telephone number) need to be conveyed at the time of auction for carrying out transactions of goods via Internet and reserving restaurants, and the like in many opportunities.
However, the mail address, the telephone number and the like are private information, and flow of its own information should be avoided. Further, an action to inquire the mail address of another person is an action to inquire the private information, so the situation is that not only a partner of whom the private information is inquired, but also an inquirer itself cannot easily cope therewith.
Thereupon, services capable of anonymously making a contact with other persons and studies/developments for it have been actively performed. For example, in Patent literature 1, a user lists a mail address of a partner that should be kept anonymous in a main text of a mail when posting the mail to a mailing list, thereby enabling the user to anonymously transmit the mail.
Further, in Patent literature 2, a user A can acquire the anonymous mail address by only transmitting the mail to an anonymous mail address issuing server when acquiring the anonymous mail address. Utilizing this anonymous mail address enables the user A to anonymously make a contact with a user B with which the user A desires to anonymously make a contact.